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The AD5681R/AD5682R/AD5683/AD5683R are a family of one channel DACs with 12-bit, 14-bit and 16-bit precision respectively. The devices have either no built-in reference, or built-in 2.5V reference. These devices are similar to AD5691R/AD5692R/AD5693/AD5693R except with a few notable differences: * they use the SPI interface instead of I2C * in the write control register, DB18 and DB17 are used for setting the power mode, while DB16 is the REF bit. This is why a new regmap type was defined and checked accordingly. * the shift register is 24 bits wide, the first four bits are the command bits followed by the data bits. As the data comprises of 20-bit, 18-bit or 16-bit input code, this means that 4 LSB bits are don't care. This is why the data needs to be shifted on the left with four bits. Therefore, AD5683_REGMAP is checked inside a switch case in the ad5686_spi_write() function. On the other hand, similar devices such as AD5693R family, have the 4 MSB command bits followed by 4 don't care bits. Datasheet: http://www.analog.com/media/en/technical-documentation/data-sheets/AD5683R_5682R_5681R_5683.pdf Signed-off-by: Stefan Popa <stefan.popa@analog.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.